Refillable cartridge-fuse.



C. T. McDONALD.

REFILLABLE CARTRIDGE FUSE.

APPLxcmnn msn omai. 191,3.

1,231,036. Mmmm 26,'1917.

@1252665 @5 IRI/mf:

UNITED STATES PATENT OFFICE.

CLARENCE T. MCDONALD, OF CHICAGO, ILLINOIS.

REFILLABLE CARTRIDGE-FUSE.

. Specication of Letters Patent.

4Patented June 26, 1917.

I Application filed December 31, 1913. Serial.No.'809,791

To aZZ whom it muy concern.'

Be it known'that I, CLARENCE T. Mc` DONALD, a citizen of the United States, re-

The object olf the invention is to provide an improved construction of the end portions or terminal heads of the fuse body, and the means forsecuring therfuslble element thereto.

Referring to the accompanying drawings, Figures 1 and 2 are longitudinal central sections through two different modifications of 4an inclosed fuse embodying the features of Iy invention. Figs. 3 and 4 are perspective views ofthe fusible elements of. the fuses shown in Figs. 1 and 2, respectively. Fig-5 is a cross sectional view taken in the plane of line 5-5 of Fig. 2.

The fuse comprises a body which includes a sleeve 10 of insulating material, and caps 11 closing the ends of'said sleeve, said caps having their flanges telescopi about the periphery of the end portions o the sleeve.`

hese caps are secured to the sleeve by a suitable number of screws 12 passing through apertures in the caps and into the sleeve. i

-In the construction shown in Fig. 1, the fuse as Whole is mounted in its supporting device by means of a pair of knifeblades 13 projecting from opposite ends of the fuse,

the inner endsi'ofsaid blades lying within the sleeve and serving to support thefusible element. The knife blades are held between sprin contact fingers on the fusesupport ing evice. In the construction shown in Fig. 2the end caps, themselves, are pressed between and held by the spring contact fingers. In Fig. 1 the end caps are'vprovided with slots through which-the knife-blades extend, and cach blade i'sV heldA in 'place by means of a cotter in 14 and a pair of U4 shaped disks or was ers 15 lying at the inner side of the ca and en aging 1n notcheslin 'the knife bla e. The usible element 16'- is secured4 to the inneniends of the knife-blades Y by means. of screws 17'.

In the construction/of Fig. 2, there is provided a pair of metallic rings 18 which fit l upon opposite ends of the sleeve 10, the caps 11 ytelescoping about these rings, and the,

Screws l2.passing therethrough. The caps are\slidable in a straight line axially of the slee\'e and rings without rotation of the caps y in placing the latter on the sleeve and rings. -The rings 18 may also be used in the construction shown in Fig. 1.

My improved fusible element .for use in these'fuses, consists of a pair of round fuse wires 19, having their ends permanently secured, as by soldering, to-a pair of end pieces or plates, which are removably clamped to the end terminal parts of the fuse. In the construction shown 'in Fig. l,

theseterminal plates 20 are in the form of Vlint pieces adapted to lie alongside the' inner ends ,of the knife-blades 13 and being clamped to'said blades by means of screws passin through the end pieces and threaded into t e knife-blades. Preferably the end pieces are bent or offset as at 21 at their inner end adjacent to the fuse wires, as clearly shown in Fig. 1 in order to position the fuse wires centrallyfof the casing.

' In Fig. 2. the end pieces 22 are in the form of strips which are angularly bent when the fuse element is to be inserted .in the body, thus formin flanges 23 adapted to lie along the inner si es of the end walls of the caps 11. These bent ends or flanges 23 have aper tures 24 therein, and said endsare clamped against the respective caps by meansv of Ascrews V25 lpassing throughV the'caps and through the a ertures 24, the 4inner ends ofsaid screws f ingl threaded in clamping pieces 26, so that when the screws are turned up, the ends 23 will be tightly clamped between the ieces 26 and the end walls of the caps 11. ach clamp piece 2 6 is in the form of a generally circular disk, having a central threaded aperture forthe screw and having a notch 27 mits periphery to` receive the end piece'of thefusi le element. The clamping disk also has a. plurality of outwardly extendin lugs 28I on' itsperiphery, said lugs lying ign notches 29 formed in the ends of the sleeve 10 andthe ring: 18. These interengaging lugs and notches 28 and 29 serve to hold the clamping disk 26 in proper position, and to prevent rotation of the disk when the screw 25 is turned up. From an inspection of Figs. 2 and 4, it will be noted 'with powdered or granular msulating material, as is'common in fuses of this class. I

have deemed it Vunnecessary to indicate such insulating material in the drawings. This powder is removed and replaced Whenever i the fuse element is renewed.

I cla-im as my invention:

1. An inclosed electric fuse of the refillable type having, in combination, a. tubular body comprising a sleeve of insulating material and two metallic rings surrounding Vand fitted upon opposite ends ofsaid sleeve and pcrmanently'secured thereto, said rings having smooth externa-l peripheries, metallic caps having tubular portions with smooth internal lperipherie's adapted to tit upon and4 telescope over said rings,` said capsbeingv slidable vin a straight line axially' of said tube and rings without rotation of the cap in placing the caps on said rings, said caps having apertures therethrough and the body having threaded metallic seats in registry with said apertures, screws adapted t0 pass through the apertures and engage in Said metallic seats foi-rigidly securing the caps to the sleeve and r1ngs,a fuse element within said sleeve, and devices independent of said cap-securing screws for releasably clamping` the opposite end portions of the fuse ele-iy ment to said caps.

2. An inclosed 'electric fuse of the refill- `able type having, in combination, a tubular body comprising a sleeie of insulatingl material and two metallic' rings surroundlng and fitted upon opposite ends of said sleeye and permanently vsecured thereto, said rings havving smoothexternal peripheries, metallic caps having4 tuliular ortions 'With'smooth -internal peripheries a. apted to fit upon and telescope over said rings, said caps being slidabl'e in a straight line axially of said tube and rings without rotation of the caps -in placing the caps on said rings, said caps having apertures therethrough and the body having threaded vmetallic seats. in registry with said apertures, screws adapted to pass through the Vapertures and engage in said metallic seats for rigidly securing the caps to the sleeve and rings, additional screws passing throu h the end Walls of the caps i With the hea. s of the screws at the outer sidcsof the caps, disks. located within the ends of the sleeve and the caps and having radial lugs engaging in recesses in the sleeve to prevent rotation of the disks, and a fuse4 element having its end portions lying be tween. said disks and the end walls of the caps, saidl end portions being clamped to the caps by salid'additional screivs.

In testimonyyvhereof I aflixmy signature I in presence of two witnesses.

'CLARENCE T. 'MeDoNALn Witnesses:

.VERENA STUART,

GEORGE L.CH1NDAHL. 

